Heretofore it has been recognized that acoustical waves can be generated and conducted through human skeletal structures for utilitarian purposes. This is generally referred to as bone conduction. The principal use to date of bone conduction has been the conduction of sound to the inner ear via the skull. This has found use in industries where workers are exposed to high noise background levels. This has also found use in military applications where communication needs to be inaudible to the naked ear.